Security inspection plays an essential role in fields of anti-terrorism, drug trading, smuggling and the like. Governments all over the world are paying more attention on combating smuggling, and inspection standards for custom containers, luggage, and other sensitive goods have been raised to a higher level. Recently, liquor smuggling appears to have perceptible impact on domestic liquor market. It not only disturbs regular economic order and causes tremendous tax loss of the nation, but also may provide funds for terrorist attacks and other criminal activities. Thus, striking liquor smuggling is of significant meaning.
Large-amount liquor smuggling is typically carried out via containers, thus ordinary inspection approaches are not capable of correctly detecting all types of liquors. Moreover, such inspection approaches normally requires opening the containers, which is not always feasible in practice. X-ray imaging preforms radiography on goods, luggage and the like, so as to conduct inspection without opening the package. X-ray imaging technology is already widely applied in airports, customs, and train stations, and currently serves as an important approach for illegal object inspection. However, in the process of image inspection, an image inspector is required to determine what is enclosed in the container being inspected, and erroneous judgments are inevitable since the number of categories of goods may be too large for a person to clearly distinguish. Furthermore, different image inspectors may vary a lot in practical experiences. Additionally, human inspection effect may reduce a lot when fatigue arises to the inspector after long time working. Therefore, intelligent inspection functionality in an automatic way is urgently demanded to assist human inspection.